Thermal junction thermostatic chamber



Dec. 13, 1966 KAZUKUNI NH 3,290,389

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United States Patent O 3,290,839 THERMAL JUNCTEGN THERMOSTATIC CHAMBERKazukuni Nil, Nishinomiya, Japan, assignor to Sumitorno Electricindustries, Ltd, Osaka, Japan, a corporation of Japan Filed Mar. 11,1965, Ser. No. 439,4l21 15 Claims. (Cl. 62-3) This invention relatesgenerally to thermostatic chambers in which objects are placed forobservation and treatment which includes programs for heating andcooling the objects under controlled conditions.

Accurate control of the thermal conditions of specimens undergoing studyand treatment has long been recognized as a valuable asset to researchand production. Many different types of structures have been constructedfor this purpose.

Semiconductor material is known to have predetermined thermalcharacteristics when made up in thermal junctions and used to produceheat and cold with accurate control to effectively spell the success ofthe treatment or experiment.

Such controls may be employed as a supplementary source of temperaturecontrol to attain the degree of accuracy. On the other hand, thesemiconductor may function as the only source of heat or cold with, ofcourse, equal or greater accuracy. The semiconductor employed may beformed into a thermal junction or other thermal electric element bywelding, soldering, brazing or otherwise applying a wall of high thermalconductivity to the crystal or crystals. These walls of high thermalconductivity when secured to the opposite faces of the crystals may thenbe finished to mate with the adjacent Wall surfaces of inner and outerhousings. These housings are also made of high thermal conductivitymaterial and can themselves function as the electric connectors forcompleting the circuit through the semiconductor junctions. However, theelectric circuits may also be connected by bus bars or heavy conductorlines, or to the walls of the housing which may be poor electricalconductors but good thermal conductors.

One object of this invention is the provision of a thermostaticallycontrolled chamber having inner and outer housings which are unitary inconstruction being made as a single casting of material of high thermalconductivity and impervious to liquids so that they may be fully orpartially immersed to cool or heat the same. Such material may becopper, aluminum, iron, steel, stainless steel or clad stainless steelwith an inner layer of copper or aluminum. Materials of this characterare impervious to liquids and therefore may be bathed in gases orimmersed in liquids to heat or cool the same.

Another object is the provision of an inner and outer chamber having acommon opening or mouth. The mouth opening is preferably formed ofinsulating material as is the lid that closes the same. The spacebetween the inner and outer chambers is filled with an insulation thatprevents the conductivity of heat therebetween except through theinterconnecting thermal junctions through semiconductors. These thermaljunctions are not as large as the adjacent faces of the housings. Thus,the thermal conductivity is concentrated at the thermal junctions. Thehousings shown are substantially square but they may be polygons of agreater number of faces or they may be cylindrical with a junction oneach face and on the bottom. Each thermal junction may be independentlymounted relative to their housing face and independently connected to anelectric circuit. Otherwise, they may be connected in groups. When notindepend ently mounted they may all be connected in to an electriccircuit.

Another object is the provision of a support for the bottom of the innerchamber within the outer chamber. Such a support may be produced by aplurality of upwardly open sockets in the inside of the bottom of theouter chamber adapted to receive and retain an insulator plug such asglass or a thermosetting resin. The upper face of such a plug or stripextending along between the inner and outer chambers which strip may beprovided with a series of circular wells for receiving coil springswhich when set in the bottom of each well and extend upwardly to engageand support the underside of the inner chamber. This spring may be madeof glass or metal and it should have sufiicient pitch so that when underload the adjacent coils will not be engaged with each other. A spring ofthis character will transmit little or no heat between the inner andouter housings.

Another and more important object of this invention is in the mountingof the semiconductor thermal junctions with high thermal conductivitybetween their opposite sides and the inner and the outer housingrespectively to a transfer of heat relative to the inner chamber,whether the heat is being supplied to the inner chamber or removed fromthe inner chamber. This thermal connection is preferably provided with amovable means of high thermal conductivity material so as to interposeat least two adjacent heat exchange surfaces to compensate for therelative expansion and contraction movement between the inner and outerchamber and their heat conducting exchange surfaces. Such a movablemeans is preferably set between aligned heat conducting surfaces and areattached to similar adjacent surfaces. If they are not so provided thepressure created by expansion and contraction may fracture the similarconductor thermal junctions.

The movable means that is effected by expansion and contraction of theconnected parts may take the form of a wedge of which one or possiblytwo of its surfaces are inclined relative to the normally disposedsurfaces of the adjacent aligned faces of the inner and outer housingswhether they be polygonal or cylindrical. The wedge may have one normalsurface and one inclined surface. The corresponding mating surfaces ofhigh thermal conductivity will, of course, be complimentary to the wedgesurfaces. A wedge of this character is provided with a spring means, oneedge of which is connected to the wedge and the other end of the springmeans being attached to some portion of the structure of thethermostatic chamber so as to continuously urge the Wedge conductingsurfaces into thermal conducting contact with the mating adjacent heatexchange surfaces in the housing. The spring means may be coil springslying one on each side of the wedge and connected to the housingstructure so as to place the springs in tension whereby their pressureconstantly urges the wedge into surface engagement with the adjacentthermal conducting surfaces. The spring means may, of course, engage thewedge and urge the wedge into thermal conducting contact with the matingadjacent heat exchange surfaces. In this way the thermal junctions willforce the wedge to relieve the pressure due to expansion before thesemiconductor thermal junction is subjected to a pressure sufficient tofracture the same.

Another move of providing a movable means between the aligned heatexchange surfaces is in the form of a spring means which can be acantilever leaf spring but is preferably hoop shaped being either in theform of a continuous oval or preformed strap spring with their endsconnected together. In each instance the spring itself forms one wall ofthe thermal junction which has considerable area matching that of themating adjacent heat exchange surfaces either on the inner or outerchamber wall with the opposite side secured to the thermal junction.Springs, cantilever or hoop type, may be constructed of high thermalconductivity material such as aluminum, copper or brass, the same may beclad by mild or stainless steel. The heat exchange surfaces of thesesprings may be welded, soldered, brazed or otherwise permanentlyconnected with the adjacent heat exchange surfaces. A particularadvantage of this character of movable means in the thermal conductingpath is that the total movement can be assumed in any direction by themere flexing of the spring without it interferring in any way with thepermanent thermal conductivity of the spring.

The thermostatic chamber made with an inner and outer housing that aresubstantially square in shape may provide a thermal junction ofsemiconductors connected to each of the four walls between the inner andouter housings and in such a structure, only two movable means need bedisposed in the thermal conducting heat exchange paths disposed at rightangles of each other; however, it is preferable to use four springs, onebetween each of the adjacent walls.

Another object is the provision of a heat exchange surface between themovable means connecting the thermal junctions and the adjacent thermalconducting surfaces wherein the thermal conducting heat exchangesurfaces have high thermal conductivity but low electrical conductivitywhich permits electrical connections to be made directly to the movablemeans on opposite sides of the thermal junction whereas the thermalcoonduction passes directly between the housing. This may be performedby using steels of low current carrying capacity made by a clad coveringhigh thermal conducting qualities. If the movable means is representedby a spring on opposite sides of the thermal junctions, the selectedstainless steel could be employed as a heat conductor but would functionas a high resistance to current flow and the circuit leads could beconnected directly to the springs or thermal junction members.

Another object of this invention is the provision of a vibrator whichmay be connected to either the inner or outer chamber or to bothchambers which vibrator can be of any type but is preferablyelectromagnetic because it requires less maintenance. By providing avibrator on either or both inner or outer chambers the whole systemincluding the movable means supporting the thermal junctions will beconstantly vibrated making their movable characteristics highlysensitive to slight changes in the expansion and contraction. This istrue whether the movable support is of the wedge type or the cantileverspring or loop spring type. The vibrations would be preferable in alldirections or in the direction of the movement of the wedge or normal tothe flexibility of the springs which in this disclosure would bedisposed at right angles relative to each other. The spring means woulddispose the thermal junctions to be vibrated in a horizontal plane andthe wedges would support the members and move in a horizontal orvertical direction. Thus, the wedges and the springs, the latter beingof sufficient circular mills to carry the heat and the electric current,will be vibrated in its plane of greatest movement making them sensitiveto slight forces of movement due to expansion and contraction of theassembly.

Another object of this invention is the provision of an insulated lidfor the thermostatic chamber for the purpose of carrying electricconnections to the interior chamber and in the inner housing, whichelectrical connections may, of course, be in a single phase ormultiphase or coaxial cable for high frequency oscillating circuits forcarrying on experiments and producing conditions under which the objectsmay be subjected to while in the thermostatic chamber. This lid may alsobe provided with a transparent window to observe the experiment withinthe chamber.

Other objects and advantages appear hereinafter in the followingdescription and claims.

The accompanying drawings show for the purpose of exemplificationwithout limiting the invention. or claims thereto, certain practicalembodiments illustrating the principles of this invention wherein:

FIG. 1 is a horizontal cross section of the thermostatic chamber havingunitary inner and outer housings connected through thermal junctions anda movable means.

FIG. 2 is a horizontal section of a thermostatic chamber having innerand outer housings connected through thermal junctions and a movablemeans wherein the chamber of the inner housing is additionallycontrolled by a circulating thermal system.

FIG. 3 is a view in side elevation of a thermostatic chamber with partsbroken away and shown in section to illustrate the inner and outerhousing connected through thermal junctions and a movable means.

FIG. 4 is a top plan view of the thermostatic chamber shown in FIG. 3.

FIGS. 5 and 6 are each views in vertical section of a thermostaticchamber with parts broken broken away to illustrate the inner and outerhousing connected through thermal junctions supported by a modified formof movable spring means.

Referring to FIG. 1 of the drawings the inner housing 1 is suspendedwithin the outer housing 2 and is connected thereto by means of aplurality of thermal junctions 3 there being at least two thermaljunctions connected in line with each other between the opposite sidesof the housings l and 2 which are polygon in shape and each surface ofthe polygon may be provided with at least two thermal junctionsconnected in line.

As shown in FIG. 1 the inner housing 1 with its inner chamber 4 issubstantially square in cross section and thus requires two sets ofopposed thermal junctions 3 to be aligned on its opposite faces andthereby connecting the inner housing 1 with the outer housing 2, theinner surface of which is also square but larger than the inner housingin order to receive the same.

Each of the housings 1 and 2 are unitary in that they are made of asingle character of material that has a high thermal conductivity and isimpervious to liquids. Such a material could be substantially anymaterial that could be welded, casted, soldered, or otherwise pressed orformed, and its walls being impervious to the seepage of liquidthereinto. A molded single piece of material is preferable for each ofthese housings. An insulating means 5 surrounds the inner chamber andoccupies substantially all of the inner space between the two housingsexcept that required for the thermal junctions, and other [movable partsassociated therewith.

As previously explained the thermal junctions 3 are preferably mountedin alignment with one on each side of the inner housing l and in directcontact with the plurality of heat exchange surfaces 6 on the outerwalls of the inner housing. Heat exchange surfaces 7 and 8 on the innerwall of the outer housing 2. These aligned heat exchange surfaces may bewelded, soldered, brazed,

. or otherwise secured to the metal plates on the op p-osite sides ofthe thermal junctions 3 which actually form the junction on oppositesides of the semiconductor indicated at 11 which mates and is secured tothe thermal heat exchange surfaces 7 to fix the thermal junctions 3 inplace. These semiconductors 11 may be single crystals or a multipleseries of crystals stacked together and soldered, brazed, welded orotherwise secured to the metal plates 10 which may be uniformly finishedon their outer faces engage or be secured for the purpose of exchangingheat with the heat exchange surfaces 6, 7 and 8.

In order that the relative expansion and contraction of each of thesemembers which are directly connected in aligned series perform the heatexchange path between the two housings, it is necessary to provide somemeans that is capable of movement so that it will allow for the ex-pansion and contraction and prevent the pressure from crushing or otherwiseinjuring the thermal junctions 3 or crushing or otherwise bending thewalls of the chambers 1 and 2. This movable means in FIG. 1 and 2 isrepresented by the wedge members 13. The wedge member in FIG. 1 isslidable on the incline surface 7 which in this instance is an integralpart of two sides of the inner wall surface of the outer housing 2. Eachwedge 13- has one parallel surface 14 and one incline surface 15. Asshown in FIG. 1 metal plate 161 on two of the thermal junctions 3,adjacent the wedges 13, functions as stationary heat exchange surfacesin engagement with the movable parallel surfaces 14 of the wedge. Thewedge surfaces 15 are in engagement with the incline heat exchangesurfaces 7 of the inner surface of the housing 2.

In order to urge the wedge into position to provide a continuous thermalconducting relation of the wedge surfaces and their adjacent heatexchange surfaces a pair of springs 16, one disposed on each side of thewedge and engaging the transverse rod 17 on the large end of each wedge.The other ends of the springs 16 are fastened to the cross plate 18which is provided with a threaded opening to provide an adjustable screwmember 20 that engages the abutment surface 21 at the point of greatestinclination of the inclined heat exchange surface 7 in which the end ofthe thumb screw Ztl has a rotary seat to hold this screw in place. Thus,by turning in the thumb screw 20 the springs 16 on either side of thewedge 13 draw the wedge tighter into thermal conducting relation withtheir adjacent heat exchange surfaces 6, 7 and 8.

When the expansion in one seat of aligned thermal junctions occurs, theforces pinch out the wedge 13, increasing the tension of the springs 16but maintaining thermal conduction relation with the adjacent heatexchange inclined surfaces 7 and the outer heat exchange surface of theplates 111 which are indicated at 22.

It will be noted that there are four thermal junctions 3, with a pair inalignment in their respective major axes of the aligned walls of thisinterchamber 1 which is in the form of a square. There may only need betwo thermal junctions employed in some installation. However, as shownin FIG. 1, there are as many thermal junctions as there are sides of thepolygon which in this instance is in the form of a square. In FIG. 2there are only two thermal junctions 3 aligned in one major axis of thehousings but the incline heat exchange surface 7 of the housing 2 asshown in FIG. 1 is not present in FIG. 2 but is formed as indicated at24- as an inner fiat heat exchange surface as a part of the wall 1 whichis stationary relative to the wedge 13 which is mounted in the samemanner to place the springs 16 in tension. The wedge 13 in this instancehas its incline surface 15 in engagement with the incline surface 24 ofthe member 23. The parallel surface 14 of the wedge is movable againstthe fixed heat exchange surface of the plate 10 which is stationaryrelative to the outer case.

Thus, the wedge 13 is reversed in its application as shown in FIGS. 1and 2. The structures of FIGS. 1

6 and 2 illustrate that the wedge may be adjacent the outer or the innerhousing respectively; however, its function if precisely the same.

As shown in FIG. 2 the chamber 4 is provided with the circulatingconduit connections 25 and 2.6 for the purposes of circulating a fluidwithin the chamber 4 of the inner housing 1. The lower thermal junctions3 in FIG. 2 has an extended or enlarged wall member 27 that forms ajunction with the semiconductor 11 and. extends to and is secured inthermal conductivity with the wall 6 of the inner housing 1.

If both of the housings 1 and 2 are made of a metal of high thermalconductivity they may be provided. with current conductors 30 and 31 forthe purposes of placing each of the thermal junctions 3 in FIG. 1 intoparallel circuit thereby control the current and the direction of thecurrent flowing through the semiconductors of the thermal junctions 3and thus determine whether or not heat is supplied to the inner chamberthrough what is knOWn as the Peltier effect. The conductors 30 and 31may be connected to insulated binding posts or terminals such as 32 and.33 as shown in FIG. 4.

Referring to FIGS. 3 and 4 the structure of the inner and outer housing1 and 2 are more elaborate and the fins are extended only on 2 sides andare larged. However, the structure of the wedge blocks 13 is similar andare operated to be urged vertically upwardly by their respective springs16 in place of horizontally as indicated. in FIGS. 1 and 2. In FIGS. 1and 2 the stationary part that is provided with a complimentary inclinesurface 7 indicated at 23 in FIGS. 1 and 2 is provided with an underlipor shelf 28 to support the underside of the wedge as it is slidhorizontally back and forth. The underlip 28 may take many forms such asa key and. slot on the wedge 13 and in the member 23 respectively.

As illustrated in FIGS. 1 and 2 a vibrator as indicated at 34 isconnected to the outer housing to vibrate the same at a high vibratoryfrequency so that the wedges will be made sensitive to movement due tothe expansion and retraction forces created by the materials of highthermal conductivity that connect the thermal junctions between theinner housing 1 and the outer housing 2.

As shown at the bottom of FIG. 3 the inner bottom wall of this outerhousing is provided with an upwardly projecting stool or section 35having a central bore to form a socket 36 for the reception of theplastic insulating holder 37 which mates with the socket 36 and islikewise provided with an upwardly open socket 38 to receive the lowerend of the spring 40 the upward end of which extends out of socket 38into engagement with the underside of the bottom of the housing 1 and isenable to resiliently support the same taking a mechanical load from thewedge surfaces in the heat exchange thermal conducting relationship.move vertically and have their incline surfaces 15 slidable against thecorresponding incline heat exchange surfaces 7 which actually form theouter aligned heat exchange surface of the wall of the inner housing 1.

One or more of the springs 40 may be employed along the bottom of thehousings. However, these springs being set in the sockets of independentinsulating resins will conduct very little heat and electricallyinsulate the inner and outer housings 1 and 2.

The upper rim of the inner housing 1 in FIG. 3 is provided with anoutwardly extending annular flange 41 in which the screw 20 is mountedto suspend the cross member 18 supporting the springs 16 to urge thewedge blocks 13 upwardly into contacting relationship.

The upper face of the flange 41 is engaged by the insulating annularmouth 42, which extends upwardly and outwardly of the insulatingmaterial 5 and defines the top 43 of the outer chamber 2. As illustratedin FIG. 4 the housings are rectangular and the annular mouth 42 In thisstructure the wedges is closed by the insulating lid 44 which carriesthe thermometer 45 and observation window 46 and a series of terminals47 and which maybe raised or lowered by the handles 48. The handles 49are placed on the outer housing 2 for carrying the thermostatic chamber.This lid may also carry a rotary shaft to rotate the specimen in thechamber 4 or to stir a mixture in the chamber 4. As illustrated in FIG.3 some of the terminals 47 are connected to an inter-heat element St)within the chamher 4. Thus, when the lid 44 is placed in sealingposition as illustrated in FIGS. 3 and 4, chamber 4 is completely sealedand. will remain in this way until open. Latch or locks may be providedto secure the lid so that it will not accidently become loosen by theoperation of the vibrator 34.

In FIGS. 5 and 6 the wedges 13 have been eliminated and the thermaljunctions 3 are supported between flexible leaf springs of high thermaland electrical conductivity. In FIG. 5, the leaf spring 51 is shownelliptical in shape and the opposite sides of its longitudinal axis 52are welded, soldered or brazed or otherwise secured to the thermaljunctions 3 on one side as indicated at 53 and to the wall of the innerchamber as indicated at 54 on its other side. Thus, any relativeexpansion or contraction movement in any direction is assumed betweenthese strap loop springs which may also function as the heat andelectrical conductor if desired. If not so desired, the wires such asillustrated. at 30 and 31 may be employed to directly connect theopposite sides of the thermal junctions 3.

In the structure of FIG. 6, the thermal junctions 3 are connected onopposite sides between strap type leaf springs 55 and 56 intermediateends of which are secured directly to the inner and outer housing wallsas indicated at 57 and 58 and the outer or free ends of the spring 55and 56 are welded, brazed or soldered or otherwise secured to thethermal junctions 3. Here again the flexure of the springs 56intermediate of their connection to form the aligned heat exchangesurfaces to provide a continuous thermal conducting relationship withthe inner and outer housings may flex to compensate for the expansionand contraction owing to the supply or withdrawal of the heat from thechamber 4 through the thermal junctions 3.

It is preferable to have the spring or straps 55 and 56 constructed ofcopper that is thicker adjacent the thermal junctions 3 than in theirflexing positions so that the flexure of these springs will not betransmitted to the semiconductors 11 and cause them to fracture.

In spring supported thermal junctions of this character it is still bestto provide a vibrator 34 so as to provide some vibration at all times tothese spring members 51 and 55 and 56 to make them sensitive to veryslight expansion and contraction forces.

I claim:

1. A thermostatic chamber for heating and cooling objects and includingan outer housing with an annular Wall of high thermal conductivity, aninner housing with an annular wall of high thermal conductivity andmounted in said outer housing, an annular insulating mouth connectingboth housings leading into a chamber in said inner housing to containthe objects to be treated, an insulating lid closing said annular mouthin both housings, insulation means between the walls of adjacenthousings including said annular mouth, a plurality of thermal junctionsincluding semiconductors having their oppositely facing ends directlyconnected to parallel walls of high thermal conductivity, a plurality ofaligned heat exchange surfaces on said adjacent housing walls and onsaid parallel thermal junction walls in continuous thermal conductingrelation to each other to complete a thermal exchange circuit betweensaid chambers, and means to connect said thermal junctions in anelectrical circuit to transfer heat relative to said inner chamber, anda movable means of high thermal conductivity material having oppositelydisposed heat conducting surfaces and interposed between at least two ofsaid mating adjacent heat exchange surfaces to compensate for therelative expansion and retraction movement between said continuousthermal conducting heat exchange surfaces of said inner and outerhousings.

2. The thermostatic chamber of claim 1 including a vibratory meansconnected to vibrate said housings to induce movement of said movablemeans to make it more sensitive to changes in thermal expansion andcontraction.

3. The thermostatic chamber of claim 1 wherein said movable means is aspring member.

4. The thermostatic chamber of claim 3 wherein said spring member is aclosed elliptically shaped flat spring with long sides providing saidheat conducting surfaces capable of greater flexibility along its minoraxis and less flexibility along its major axis.

5. The thermostatic chamber of claim 1 wherein said movable means is awedge, and spring means connected to said wedge to continuously urgesaid wedge conducting surfaces in thermal conducting contact with saidmating adjacent heat exchange surfaces.

6. A thermostatic chamber for heating and cooling objects and includingan outer housing with an annular wall of high thermal conductivity, andinner housing with an annular wall of high thermal conductivity andmounted in said outer housing, an annular insulating mouth connectingboth housings leading into a chamber in said inner housing to containthe objects to be treated, an insulating lid closing said annular mouthin both housings, insulation means between the walls of adjacenthousings including said annular mouth, a plurality of thermal junctionsincluding semi-conductors having their oppositely facing ends directlyconnected to parallel walls of high thermal conductivity, a plurality ofaligned heat exchange surfaces on said adjacent housing walls and onsaid parallel thermal junction walls in continuous thermal conductingrelation to each other to complete a thermal exchange circuit betweensaid chambers, and means to connect said thermal junctions in anelectrical circuit to transfer heat relative to said inner chamber, anda wedge member of high thermal conductivity material having oppositelydisposed heat conducting surfaces at least one of which is inclined,said wedge conducting surfaces complementary to and mating in slidingcontact with at least two of said mating adjacent heat exchangesurfaces, and spring means connected to said wedge to continuously urgesaid wedge conducting surfaces in thermal conducting contact with saidmating adjacent heat exchange surfaces.

7. The thermostatic chamber of claim 6 wherein said inclined wedgeconducting surface is adjacent and complementary to said heat exchangesurface on said outer housing.

8. The thermostatic chamber of claim 6 wherein said inclined wedgeconducting surface is adjacent and complementary to said heat exchangesurface on said inner housing.

9. The thermostatic chamber of claim 6 wherein said inclined wedgeconducting surface is adjacent and complementary to said heat exchangesurface on one wall of said thermal junction.

10. The thermostatic chamber of claim 2 characterized by a circulatingfluid cell in said inner housing to transfer heat relative to said innerchamber.

11. A thermal transfer junction having semiconductor thermal junctionmeans with oppositely facing surfaces to be secured to spaced heatexchange surfaces characterized by a movable means of high thermalconductivity material having oppositely disposed heat conductingsurfaces interposed between one of said heat exchange surfaces and saidsemiconductor thermal junction means to compensate for the relativeexpansion and contraction movement in exchanging heat.

12. The thermal transfer junction of claim 11 wherein said movable meansis a spring means to compensate for r l ive exp nsion and contractionmovement.

13. The thermal transfer junction of claim 11 wherein said movable meansis a wedge with biased pressure means to maintain thermal contact therebetween to compensate for relative expansion and contraction movement.

14. The thermostatic chamber of claim 1 characterized in that said innerhousing is unitary and impervious to liquids.

15. The thermostatic chamber of claim 1 characterized in that said outerhousing is unitary and impervious to liquids.

References Cited by the Examiner UNITED STATES PATENTS Ryan 623 Bury62--3 Kistler 623 Petrie 62-3 Eidus 623 10 WILLIAM J. WYE, PrimaryExaminer.

UNITED STATES PATENT OFFICE CERTIFI"(TN CORRECTION Patent No. 3, 290,889 December 13, 1966 Kazukuni Nii It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 7, line 71 and column 8, line 37, for "chambers", eachoccurrence, read housings Signed and sealed this 19th day of September1967.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER AttestingOfficer

1. A THERMOSTATIC CHAMBER FOR HEATING AND COOLING OBJECTS AND INCLUDINGAN OUTER HOUSING WITH AN ANNULAR WALL OF HIGH THERMAL CONDUCTIVITY, ANINNER HOUSING WITH AN ANNULAR WALL OF HIGH THERMAL CONDUCTIVITY ANDMOUNTED IN SAID OUTER HOUSING, AN ANNULAR INSULATING MOUTH CONNECTINGBOTH HOUSINGS LEADING INTO A CHAMBER IN SAID INNER HOUSING TO CONTAINTHE OBJECTS TO BE TREATED, AN INSULATING LID CLOSING SAID ANNULAR MOUTHIN BOTH HOUSINGS, INSULATION MEANS BETWEEN THE WALLS OF ADJACENTHOUSINGS INCLUDING SAID ANNULAR MOUTH, A PLURALITY OF TERMAL JUNCTIONSINCLUDING A SEMICONDUCTORS HAVING THEIR OPPOSITELY FACING ENDS DIRECTLYCONNECTED TO PARALLEL WALLS OF HIGH THERMAL CONDUCTIVITY, A PLURALITY OFALIGNED HEAT EXCHANGE SURFACES ON SAID ADJACENT HOUSING WALLS AND ONSAID PARALLEL THERMAL JUNCTION WALLS IN CONTINUOUS THERMAL CONDUCTINGRELATION TO EACH OTHER TO COMPLETE A THERMAL EXCHANGE CIRCUIT BETWEENSAID CHAMBERS, AND MEANS TO CONNECT SAID THERMAL JUNCTIONS IN ANELECTRICAL CIRCUIT TO TRANSFER HEAT RELATIVE TO SAID INNER CHAMBER, ANDMOVABLE MEANS OF HIGH TERMAL CONDUCTIVITY MATERIAL HAVING OPPOSITELYDISPOSED HEAT CONDUCTING SURFACES AND INTERPPOSED BETWEEN AT LEAST TWOOF SAID MATING ADJACENT HEAT EXCHANGE SURFACES TO COMPENSATE FOR THERELATIVE EXPANSION SURFACES TO MOVEMENT BETWEEN SAID CONTINUOUS THERMALCONDUCTING HEAT EXCHANGE SURFACES OF SAID INNER AND OUTER HOUSING.